Why is Flash reccomended for boot drive?

[NorCalTechSupport]

I am building my first FreeNAS box a brand new SuperMicro 24 drive jbod. I added the two drive enclosure that sticks out the backside to add a pair of 2 1/2" drives. Yes I have a fistful of new Flash drives 8GB to 32GB but my boss likes the idea of installing onto a Enterprise edition of a laptop drive. My project is about 2 days along and so far I have installed FreeNAS onto a 2 1/2" drive and am busy learning how things work.

I do have one other question pertaining to SuperMicro Chassis and that is why do the drive indicator lights work on SAS and only occasionally flash for SATA drives. My test setup has one each of SAS Enterprise 1TB drive and a SATA Enterprise 3TB drive. I asked several vendors this question as I had been warned the drive lights might not work for SATA and all the vendors said oh the SATA drive lights will work fine and now I am seeing they don't. Anyone with any ideas? The good news is have not ordered the 24 drives of whatever type I will need as I am in testing mode.

 

[cyberjock]

The SATA spec provides for SATA lights to be supported. Here's the detailed info...

HDD activity lights can be activated by either hard drives themselves http://en.wikipedia.org/wiki/Serial_ATA#Power_connectors. See pin 11 is for staggered spinup AND activity. *If* the hard drive manufacturer chooses to use this function, then it can. As far as I know the only SATA drives I've seen that work this way were Seagates. When the drive is actually busy it triggers the light. Some will only light up on actual disk writing (and not seeking) so they will flash so fast that you might not even be able to see that they are lit. This is totally optional and NOT required per the SATA spec (just like delayed spinup of hard drives is not required for SATA either). I don't have access to the detailed SAS specs anymore so I can't vouch for that personally (but I've been told it is required for SAS).

You can also get HDD activity lights by having a passive connection that monitors the SATA/SAS connection. When bits are being passed through the SATA/SAS connector then this external circuit turns the light on. Usually, this external circuit will be on the chassis/backplane. Note that this only shows data being transferred across the SAS connection, so it's not a true indicator of disk activity. But you can rest assured that any SATA/SAS activity will be preceeded by or followed by disk activity. Since you don't need that kind of accuracy with a simple disk light nobody will care. Again this is not required in the slightest for proper function, so only the higher quality stuff might have this. Normally I'd expect Supermicro to be higher quality, but you provided no model number. I know some designs from 5+ years ago don't offer this, so you might be using some old chassis.

So, what can we likely ascertain about your setup. Your backplane/chassis doesn't support the hdd activity lights via the backplane itself (or its disabled by some jumper on the backplane) AND your disks don't appear to use the activity LED connections in a way that makes them work for you.

There's some other more detailed info on this, but it quickly turns into a 100 possible scenarios solution and the reality is that you won't have any control to make the light work (or not work).

I've heard that if you deliberately enable the delayed spinup on some controllers it basically makes the LED non-functional. But I haven't seen that personally.

Flash is recommended because it's cheap, it's reliable enough for this application, and it works.

 

[NorCalTechSupport]

The SATA spec provides for SATA lights to be supported. Here's the detailed info...

HDD activity lights can be activated by either hard drives themselves http://en.wikipedia.org/wiki/Serial_ATA#Power_connectors. See pin 11 is for staggered spinup AND activity. *If* the hard drive manufacturer chooses to use this function, then it can. As far as I know the only SATA drives I've seen that work this way were Seagates. When the drive is actually busy it triggers the light. Some will only light up on actual disk writing (and not seeking) so they will flash so fast that you might not even be able to see that they are lit. This is totally optional and NOT required per the SATA spec (just like delayed spinup of hard drives is not required for SATA either). I don't have access to the detailed SAS specs anymore so I can't vouch for that personally (but I've been told it is required for SAS).

You can also get HDD activity lights by having a passive connection that monitors the SATA/SAS connection. When bits are being passed through the SATA/SAS connector then this external circuit turns the light on. Usually, this external circuit will be on the chassis/backplane. Note that this only shows data being transferred across the SAS connection, so it's not a true indicator of disk activity. But you can rest assured that any SATA/SAS activity will be preceeded by or followed by disk activity. Since you don't need that kind of accuracy with a simple disk light nobody will care. Again this is not required in the slightest for proper function, so only the higher quality stuff might have this. Normally I'd expect Supermicro to be higher quality, but you provided no model number. I know some designs from 5+ years ago don't offer this, so you might be using some old chassis.

So, what can we likely ascertain about your setup. Your backplane/chassis doesn't support the hdd activity lights via the backplane itself (or its disabled by some jumper on the backplane) AND your disks don't appear to use the activity LED connections in a way that makes them work for you.

There's some other more detailed info on this, but it quickly turns into a 100 possible scenarios solution and the reality is that you won't have any control to make the light work (or not work).

I've heard that if you deliberately enable the delayed spinup on some controllers it basically makes the LED non-functional. But I haven't seen that personally.

Flash is recommended because it's cheap, it's reliable enough for this application, and it works.

 

[NorCalTechSupport]

I found out from SuperMicro themselves that their servers, jbods etc don't support lighting the front panel light if SATA is used and it has been that way from the beginning for them. If you use a SAS drive there is a pretty blue light that turns red if the drive is dead or in a hot-spare pool. If you use a SATA drive a blue light will bling when data passes through but that is it.

 

[jgreco]

I found out from SuperMicro themselves that their servers, jbods etc don't support lighting the front panel light if SATA is used and it has been that way from the beginning for them. If you use a SAS drive there is a pretty blue light that turns red if the drive is dead or in a hot-spare pool. If you use a SATA drive a blue light will bling when data passes through but that is it.

It's a lot more complex than that.

 

[NorCalTechSupport]

I am building my first FreeNAS box a brand new SuperMicro 24 drive jbod. I added the two drive enclosure that sticks out the backside to add a pair of 2 1/2" drives. Yes I have a fistful of new Flash drives 8GB to 32GB but my boss likes the idea of installing onto a Enterprise edition of a laptop drive. My project is about 2 days along and so far I have installed FreeNAS onto a 2 1/2" drive and am busy learning how things work.

I do have one other question pertaining to SuperMicro Chassis and that is why do the drive indicator lights work on SAS and only occasionally flash for SATA drives. My test setup has one each of SAS Enterprise 1TB drive and a SATA Enterprise 3TB drive. I asked several vendors this question as I had been warned the drive lights might not work for SATA and all the vendors said oh the SATA drive lights will work fine and now I am seeing they don't. Anyone with any ideas? The good news is have not ordered the 24 drives of whatever type I will need as I am in testing mode.

Here is the answer from SuperMicro to my salesman named Kevin:
" Kevin,
Unable to make any modification for your customer request. All our backplane are designed the same since we first time release it. It is hardcoded.
When user install SAS drive, the blue (green) LED will turn on solid. Will blink when there is activity.
If user install SATA drive, the blue (green) LED will not turn on. Will blink when there is activity.
"

 

[jgreco]

Again, as I said, it's a lot more complex than that. Supermicro support isn't likely to be interested in teaching you the ins and outs of all this, which includes such arcane knowledge as SES2, and how sideband cables are used to handle SGPIO or I2C to manage the backplane.